Method of preparing 3,9-bis-(aminoalkyl)-2,4,8,10-tetroxaspiro {8 5,5{9 undecan

ABSTRACT

The yield of 3,9-bis(aminoalkyl)-2,4,8,10-tetroxaspiro (5,5) undecanes from the catalytic hydrogenation of the corresponding 3,9-bis(cyanoalkyl)-2,4,8,10-tetroxaspiro (5,5) undecanes is increased over known methods, and the recovery of the product from the hydrogenation mixture is facilitated if the dinitrile is hydrogenated in the molten condition in the presence of ammonia and a Raney cobalt or nickel formate catalyst in the absence of a solvent or diluent.

United States Patent [72] Inventors Kazumilijima Kawasaki-shi; YoshiokiKomachiya, Yokohama-ski; Eiji Negoro, Kawasaki-sin, all of Japan [21]Appl. No. 727,686

22 Filed May 8, 1968 [45] Patented Sept. 28, 1971 [73] AssigneeAjinomoto Co., Inc.

Tokyo, Japan [32] Priority May 12, 1967 [54] METHOD OF PREPARING3,9-BIS- (AMlNOALKYL)-2,4,8,IO-TETROXASPIRO [5,5]UNDECAN 3 Claims, NoDrawings [52] US. Cl 260/340.7 [5 l] lnt. Cl C07d 15/04 [50] Field ofSearch 260/3407, 340.9

[5 6] References Cited OTHER REFERENCES Chemical Abstracts, Vol. 43,1949, col. 6652(g) (Abstract of Swiss Patent No. 244,837) (June 16,1947).

Primary Examiner-Alex Mazel Assistant Examiner-James H. TumipseedAtwrneyKurt Kelman METHOD OF PREPARING 3,9-BIS-(AMINOALKYL)-2,4,8,l-TETROXASP1RO [5,51UNDECAN This invention relates to animprovement in the preparation of3,9-bis(aminoalkyl)-2,4,8,l0-tetroxaspiro[5,5lundecane which is adiamine of the formula by catalytic hydrogenation of the correspondingdinitrile of the formula which is3,9-bis(cyanoalkyl)-2-4-8-10-tetroxaspiro[5,5]undecane, R in the formulabeing alkyl having 2 to carbon atoms, the compounds represented by theabove formulas being referred to hereinafter as the diamine" and thedinitrile.

The diamine is a known curing agent for epoxy resins and may be used forpreparing polyamides and polyurethanes.

It is known from US. Pat. No. 2,996,517 to hydrogenate the dinitrile inan inert solvent with a Raney nickel catalyst at temperatures of 100 to125 C. and hydrogen pressures of 50-150 psi. The yields are 60 to 80percent. Recovery of a pureproduct from the hydrogenation mixture isrelatively difficult because of the need for removing the solvent andthe byproducts formed in substantial amounts.

It is the object of this invention to improve the known hydrogenationmethod so as to increase the yield and to facilitate the recovery of apure diamine.

We have found that the dinitrile as well as the diamine are stable in ahydrogen atmosphere at and above the respective melting points, and thatthe diamine can be obtained at practically 100 percent yield from thedinitrile by introducing hydrogen under pressure into the dinitrilewhich is in the molten state, in the absence of any solvent or diluent.We have further found that ammonia in the hydrogenation mixtureincreases the yield and suppresses the formation of undesirablebyproducts, and that Raney cobalt and nickel formate catalysts incontact with the dinitrile are superior to Raney nickel catalysts forthe purpose of the instant invention.

We have successfully hydrogenated many dinitriles of the above fonnulawhich are readily prepared by the method of the afore-mentioned patentfrom formyl nitrile or its alkyl acetal and pentaerythritol in thepresence of an acid catalyst. They are crystalline materials whosemelting points are under 1 10 C and whose melts are very viscous. Theviscosity of the melts has been found not to interfere with rapidhydrogenation.

The amount of ammonia present in the hydrogenation mixture need not becontrolled closely. Good results are generally obtained when the mixturecontains 0.5 to 4 mole percent based on the dinitrile originallypresent, but these limits are not critical. The formation of undesiredbyproducts is entirely suppressed when the partial pressure of theammonia in a closed hydrogenation vessel is between 1 and 8.5 kg./cm.when reduced to room temperature (l5-20 C.). The preferred partialpressure of ammonia is 2 to 8.5 kg./cm. The preferred partial pressurecorresponds to the equilibrium vapor pressure of liquid ammonia betweenC. and +35 C and is readily maintained by connecting the reaction vesselwith a sealed container holding liquid ammonia and maintained at thedesired temperature, which may be the ambient temperature under mostconditions.

The preferred Raney cobalt catalystsfor the method of the invention maybe prepared by developing binary or tertiary cobalt-aluminum alloys in aconventional manner, either cobalt-aluminum or cobalt-manganese-aluminumalloys being suitable. For best results, convenient recovery of thediamine and of the catalyst, the amount of Raney cobalt present in thehydrogenation mixture should be between 0.5 and 10 percent of thedinitrile. A weight range of 3 to 10 percent is preferred for a nickelformate catalyst.

The hydrogen pressure is preferably held at 20 to 150 kg./cm. but may beas low as 10 or as high as 300 kg./cm. The hydrogenation temperaturemust be higher than the melting point of the dinitrile used at theprevailing pressure, and is preferably between 1 10 and 150 C., butother temperatures between C. and 200 C. have been used with at least afair measure of success. The hydrogenation is usually completed within30 to minutes.

The hydrogenation mixture essentially consists of the molten diamine andthe catalyst when pressure is released from the reaction vessel, wherebythe ammonia present is dissipated. The dispersed catalyst can beseparated from the molten diamine by filtration or centrifuging, and theviscous liquid may then be permitted to solidify. It does not requirepurification for many applications but may be distilled in a vacuum ifunusually high purity requirements have to be met. The yield of thedistilled diamine is higher than 90 percent based on the originaldinitrile. There are no byproducts in significant amounts.

The hydrogenation vessel may be filled with the dinitrile as acontinuous phase to about 80 percent of its capacity so that a desiredbatch size can be confined in pressure vessels much smaller than thoseemployed heretofore when the vessel also had to accommodate substantialamounts of solvent.

The following examples are further illustrative of this invention.

EXAMPLE 1 A 300ml. stainless steel autoclave equipped with anelectromagnetic stirrer was charged with 150 g. 3,9-bis(2-cyanoethyl)-2,4,8,l0-tetroxaspiro[5,5lundecane (M.P. 72 C.) and 3 g.Raney cobalt catalyst. It was then closed and connected with a pressurebottle containing liquid ammonia at 20 C., whereby the pressure rose by8.5 kg./cm. Hydrogen was admitted to the autoclave until the internalpressure reached atm., and the autoclave was held in an oil bath at C.for 30 minutes while the stirrer was operated. The hydrogen absorptionhad come to an end by that time.

The autoclave was cooled to about 60 C. and it was then opened, and itscontents were quickly filtered. The filtrate was distilled in a vacuum,and 147.5 g. pure 3.9-bis(3-aminopropyl)-2,4,8,l0-tetroxaspiro[5,5lundccane (95.5 percent yield)were recovered as a fraction boiling at 204 C. at 3 mm. Hg. The compoundmelted at 52.4-52.8 C. (uncorr.)

it was identified by the absorption bands in its infrared spectrum at3,400 cm., 3,320 cm., and l,600-cm. due to the amino group, and at1,2001,l'00 cm. due to the spiroacetal group. lt was further identifiedas C ,l-l ,,O.,N by elementary analysis:

Calculated: 56.91% C; 9.55% H; 10.21% N Found: 56.66 9.88 10.17

The yield was 96.1 percent when the initial ammonia pressure was reducedto 4 kg./cm.

in an analogous manner, 100.0 g. 3,9-bis(2-cyanoethyl)-'2,4,8,10-tetroxaspiro[5,5 lundecane were converted to 99.5 g. 3,9-bis(3-aminopropy)-2,4,8, l 0-tetroxaspiro[ 5,5 lundecan'e (96.6 percentyield) by means of a catalyst developed from 2 g.cobalt-manganese-aluminum alloy.

When 100 g. of the same dinitrile were hydrogenated at an ammoniapressure of 8 kgJcm. and a hydrogen pressure of 100 l g./cm. at C. for90 minutes in the presence of 5 g. nickel formate, 94.1 g. of thediamine were obtained for a yield of 9 1.3 percent.

EXAMPLE 2 hydrogenated in the autoclave described in example i with 5 g.Raney cobalt at an ammonia gas pressure of 6 kgjcm. (10 C.) and ahydrogen pressure of 70 kg./cm. at 130 C. for 25 minutes.

The hydrogenation mixture was worked up as described in example 1, and97.2 g. 3,9-bis(l,l-dimethyl-3-cyanopropyl)- 2,4,8,l0-tetroxaspiro[5,5]undecane (97.2 percent yield) were recovered as a fraction boiling atl95-l97 C. at l-2 mm. Hg, and melting at l20l22 C. The material showedlR absorption bands at 3,400 cm., 3,320 cm", and 1,600 cm. (Ni-l and wasidentified by its elementary analysis:

Calculated: 63.69% C; 10.61% N; 7.82% H Found: 63.78 10.76 7.77

EXAMPLE 3 Higher homologs of the dinitriles referred to in examples 1and 2 were hydrogenated in the same equipment in respective runsfollowing closely similar procedures. Table 1 lists the specific meaningof R in the above formulas for each run, the melting point of thedinitrile, the initial partial pressures of ammonia and hydrogen in thehydrogenation vessel at room temperature, the hydrogenation temperatureand time, the yield of diamine in mole percent of the dinitrile used,and the boiling and melting points of the dinitrile whose compositionwas confirmed by elementary analysis in each instance.

The initial charge included 100 g. dinitrile and 5 g. Raney cobalt ineach run.

TABLE 1 R ll-CtHs li-csll c n-csll z n-CmII M.P. C., dinitrile. 78.5-79. 0 48 85 Hydrogenation:

N15 kg. !ern.' 7.5 8.3 5.2 10.0 Hz, l g./ !I1'1. 95 107 120 100 Temp, C140 120 110 150 Time, min 60 80 90 80 Diarnine:

Yield, percent. 97. 0 9.3. 5 98. 0 J3. 2 B.P., C. 'n1m. Hg. 205-20712217-221JOJ2 220240/0.15 c 11.1 C 55-57 45 74-75 J4 In an otherwiseidentical second series of runs, the Raney cobalt was replaced by 5 g.nickel formate, and respective slightly lower yields of 92 percent, 90.5percent, 94.0 percent, and 91.0 percent were obtained.

EXAMPLE 4 The effect of solvent admixtures on the hydrogenation of3,9-bis( 2-cyanoethyl)-2,4,8, l 0-tetroxaspiro{ 5 .5 ]undecane wasdetermined in the aforedescribed equipment under the conditions ofexample 1 as far as not stated otherwise. 50 g. dinitrile werehydrogenated in the presence of 1.5 g. Raney cobalt, 50 ml. solvent, ifany, with hydrogen at 100 atm. at 140 C. with stirring. Thehydrogenation mixture was filtered to remove the catalyst andfractionated in a vacuum to recover3,9-bis(3-aminopropyl)-2,4,8,10-tetroxaspiro[5,5] undecane having aboiling point of l62l63 C. at 1.5 mm. Hg.

The solvent employed, the time required to complete the absorption ofhydrogen, and the yield are listed in table 2 for each run.

Table 2 Solvent Diamine yield, k Time. min.

Liquid ammonia 28% Aqueous Ammonia 77 3O Methanol sat'd. with NH: 82 30i-Propanol satd. with NH 83 35 Water 65 40 None 96.5 '20 Ammonia wassupplied to the last run listed in table 2 in the manner described inexample 1.

When the hydrogenation tests, whose results are listed in Table 2, wererepeated with other catalysts, the yields obtained, if any, were too lowfor preparation of the diamines on an industrial scale. The catalyststested without success or with inferior results included Raney nickel,nickel on diatomaceous earth, palladium, platinum, rhodium, andruthenium.

by catalytic hydrogenation, in said formulas R being alkylene having twoto ten carbon atoms, the improvement in the hydrogenation whichcomprises:

a. confining said dinitrile in a closed vessel;

b. introducing hydrogen into said confined dinitrile under a pressure of10 to 300 kg./cm. when reduced to room temperature while said dinitrileis in the molten state at a temperature between 70 and 200 C. and incontact with a nickel formate or Raney cobalt catalyst; and

c. maintaining in said vessel a partial ammonia pressure between 1 and8.5 kg./cm. when reduced to room temperature, and sufficient to maintainin the molten dinitrile an ammonia concentration effective forsubstantially completely suppressing the formation of byproducts otherthan said diamine.

2. in a method as set forth in claim 1, said dinitrile constituting acontinuous phase in said vessel, said catalyst being dispersed in saidmolten dinitrile.

3. In a method as set forth in claim 2, said catalyst being dispersed insaid continuous phase in an amount of 0.5 to 10 percent by weight.

2. In a method as set forth in claim 1, said dinitrile constituting acontinuous phase in said vessel, said catalyst being dispersed in saidmolten dinitrile.
 3. In a method as set forth in claim 2, said catalystbeing dispersed in said continuous phase in an amount of 0.5 to 10percent by weight.